Hitherto, many image-forming methods utilizing photo-polymerization systems are known. For example, the following methods are known: a method of forming a negative-working photosensitive material comprising an addition polymerizable compound containing an ethylenical double bond, a photopolymerization initiator, and, if desired, an organic high molecular weight binder, a thermal polymerization inhibitor, etc., on a support as a coating layer, image-exposing the desired image portions of the coating layer to a desired image to harden by polymerization the exposed portions, and dissolving off the unexposed portions to form a hardened relief image; a method of forming a layer of the above-described negative-working photosensitive material between two supports at least one of which is transparent and, after image-exposing from the transparent support side to induce the change of the adhesive strength by light, releasing the support to form an image; a method of forming a photosensitive material having formed a microcapsule layer having a photopolymerizing composition and a coloring material such as a leuco dye, etc., as the content, image-exposing the photosensitive material to photo-harden the microcapsules at the exposed portions, and rupturing the microcapsules at the unexposed portions by a press-treatment or a heat treatment to color by contacting the content and a coloring material developer, whereby colored images are formed; an image-forming method of utilizing the change of a toner attaching property of a photopolymerizing composition by light; an image-forming method of utilizing the change of the refractive index of a photopolymerizing composition with light, etc.
Recently, with the development of an image-forming technique, a photopolymer having a high sensitivity to a light of a visible region as a photosensitive material suitable for, for example, non-contact type projection light-exposure plate making, visible laser plate making, etc., has been demanded. As a light of a visible laser used in this case, the 488 nm light of an Ar.sup.+ laser, the 532 light of a YAG-SHG laser, etc., have been considered to be useful.
In such a photopolymer polymerizing system, a high sensitization is an important factor and many photosensitive systems utilizing a radical polymerization profitable for the high sensitization have been investigated and developed. However, a radical polymerization system tends to receive a polymerization hindrance with oxygen, an attempt of forming a protective layer excellent in the oxygen interceptive property on the polymerization layer has been made. This is described in detail in U.S. Pat. No. 3.458,311 and JP-A-55-49729 (the "term" as used herein means an "unexamined published Japanese patent application"). Also, water-soluble polymers such as polyvinyl alcohol, polyvinyl pyrrolidone, acidic celluloses, etc., are known as such a material excellent in the oxygen interceptive property.
However, when a hydrophilic layer comprising such a water-soluble polymer is laminated on an oleophilic polymerization layer, layer separation tends to occur due to lack of an adhesive force, and the separated portions cause the faults such as a poor hardening of the layer by the polymerization hindrance with oxygen. Thus, it becomes important to sufficiently improve the adhesive force between these two layers, and various attempts for improving the adhesive property are proposed. For example, JP-A-47-469 and JP-A-49-70702 describe that a sufficient adhesive property is obtained by mixing 20 to 60% by weight of an acrylic emulsion or a water-insoluble vinyl pyrrolidone-vinyl acetate copolymer with a hydrophilic polymer mainly comprising polyvinyl alcohol and laminating the mixture on the polymerization layer. However, the method may be effective for the adhesive property with a protective layer, but because the addition amount of the mixture to polyvinyl alcohol is relatively large, the oxygen intercepting power is decreased and the sensitivity is insufficient, or there is a problem that when after light-exposure, the photopolymer layer is subjected to a development treatment with an aqueous alkali solution, the water-soluble polymer is insufficiently released in a suitable development condition, which results in easily causing a poor inking property.